Chapter 1
 Chapter 2
 Chapter 3
 Chapter 4
 Chapter 5
 Chapter 6
 Chapter 7
 Chapter 8
 Chapter 9
 Chapter 10
 Chapter 11
 Chapter 12




We all recognize that who says it matters in persuasion. However, we may not fully appreciate the dynamics of communicator effects. This chapter explores source, or communicator, factors, using theory and research to illuminate these issues. The elusive concept of charisma is introduced, along with clarification of the concept's complexities and limitations. The chapter moves to a discussion of authority, focusing on Milgram's classic study of obedience. Credibility is then defined and decomposed. The discussion of credibility is intended to help students appreciate the elements of the concept, contextual effects, and the role that audience perceptions play in credibility judgments. The remainder of the chapter describes liking, similarity, and physical attractiveness effects. The focus is on explaining why and when these communicator factors work, as well as the role that cultural factors play in the physical attractiveness effect.


Milgram experiments
Authority effects in real life
Good will
Knowledge bias
Reporting bias
Physical attractiveness


Charisma: quality of the individual that sets him or her apart from others; seemingly magical set of qualities encompassing credibility, powerful language, social sensitivity, and attractiveness.
Authority: communicator whose power comes not from personal qualities, but his or her perceived position in a social structure.
Compliance: adopting a behavior, at least in part, because of a desire to obtain specific rewards or avoid punishments.
Internalization: accepting recommendations because the message is congruent with values or attitudes.
Identification: accepting a communicator's recommendations because one identifies with the communicator, or wants to establish a positive relationship with him or her.
Credibility: attitude toward a source of communication held at a particular time by a message receiver. It consists primarily of expertise, trustworthiness, and good will.
Expertise: knowledge or ability ascribed to the communicator.
Trustworthiness: perceived honesty, character, and safety of communicator.
Good will: perceived caring or empathy.
Knowledge bias: the presumption that a communicator has a biased view toward an issue,
as a function of his or her background. Communicators who violate the knowledge bias can enhance credibility.
Reporting bias: the perception that the communicator has opted not to report or disclose certain factors or points of view. Communicators who violate the reporting bias can enhance credibility.


  1. The classic Milgram experiments have stimulated a number of questions worthy of discussion, including the following: (1) How do the findings illustrate the power that situations exert on behavior?; (2) Do you share the critics' reservations, or do you agree with those who hold that the findings were genuine?; and (3) Do you believe the study still has implications for today or is, instead, a "period piece" that applies more to earlier eras than today?
  2. Summarize the knowledge and reporting bias concepts. Next, thinking of current events in the news and entertainment worlds, offer some examples of real-life communicators who seemed to have gained credibility by violating the knowledge or reporting bias. Turning this around, think of situations in which communicators might actually lose credibility -- or not gain it -- by violating knowledge or reporting biases. This could include institutional communicators (for example, tobacco companies who sponsor anti-smoking or pro-environmental communications may not benefit from the knowledge bias).
  3. Do you believe that standards for physical attractiveness are universal or vary with culture? Discuss, considering implications for persuasion.
  4. Do audiences evaluate female communicators by different standards than they do men? Are female communicators disadvantaged when it comes to persuasion, or can they be every bit as compelling as male communicators? Similarly, are minorities judged by different criteria than White communicators? Are minorities at a strategic disadvantage when it comes to persuading mainstream White audiences? Conversely, could it be argued that race no longer matters in persuasion, or that in some situations African-Americans have a cultural advantage? Discuss these issues.


  1. The main finding of the Milgram experiments is that:
    a. a small minority of people administered heavy electric shocks, in the presence of the lab-coated scientist
    b. those who delivered electric shocks scored high on psychological maladjustment
    c. nearly two-thirds of subjects delivered strong electric shocks, in the presence of the experimenter
    d. half of the subjects resisted authority, rejecting the experimenter's demands
  2. Which of these is NOT true of the Milgram studies?
    a. subjects who conformed did so in part because they were afraid of the psychological consequences of challenging the experimenter
    b. the experimenter coerced respondents into going along; persuasion was not involved
    c. obedience was more likely when the experimenter sat a few feet from the teacher than when he gave the orders by telephone
    d. the trappings of the experiment, including the experimenter's lab coat and gender, may have increased pressure to conform
  3. Credibility is defined as:
    a. message recipients' attitudes toward a communicator
    b. titles and credentials accumulated by communicator
    c. likability and charm
    d. ability to reward audience members
  4. Which of these is NOT true about credibility?
    a. credibility emerges in the transaction between source and message receiver
    b. credibility has several components
    c. different facets of credibility can be influential in different contexts
    d. speakers who have authority possess credibility
  5. According to the knowledge bias, which of these should be most persuasive giving a speech against drugs?
    a. U.S. Surgeon General
    b. impoverished, but rehabilitated, ex-drug user
    c. likable spokesperson from Partnership for a Drug-Free America
    d. celebrity actor
  6. You are trying to decide whether to use a physically attractive communicator as a spokesperson for a campaign. Which of these statements is accurate and, therefore, of use to you?
    a. physical appeal is a peripheral factor that has no impact on persuasion
    b. physical attractiveness has a stronger effect for female than male speakers
    c people go along with attractive communicators because they like and identify
    with them
    d. since attractiveness is the same as credibility, you can be assured that an attractive spokesperson will be perceived as credible

Answers: 1: c, 2: b, 3: a, 4: d, 5: b, 6: c


  1. Select a charismatic communicator -- either someone from contemporary life, or a historical figure (political leader, activist, cult leader, etc.). Read up on this person and study his or her communication style. What makes or made the individual charismatic? Which communicator qualities (for example, credibility, language, nonverbal communication, and social sensitivity) were most important? How did the communicator's interplay with the audience increase his or her charismatic appeal? In the case of the historical figure, do you believe he or she would be charismatic today; why or why not?
  2. Observe persuasive communicators plying their trade. Specifically, observe and interview a communicator who effectively uses expertise, trustworthiness, good will, or social attractiveness. You might focus on salespeople, including car salesmen and women, lawyers, rabbis, reverends, or priests, health care practitioners, campus leaders, or waiters and waitresses trying to solicit tips. How do they try to gain credibility or social attractiveness? What makes them credible or likable? Write up your report in an interesting way, calling on concepts from chapter 6.


Back in January, 2002, a scandal erupted involving Fortune 500 energy giant, Enron, and the Arthur Andersen accounting firm. Enron went bankrupt due to mismanagement, rampant exaggerations of its earnings, and risky, fraudulent business practices. The global, well-heeled accounting firm, Arthur Andersen, served as a major consultant and auditor of Enron's finances. With federal government investigations and numerous legal suits pending, officials at Andersen deliberately destroyed -- shredded -- thousands of email messages and paper documents relating to Enron's unorthodox financial practices. Presumably, executives like Andersen's David B. Duncan, who ordered the destruction of documents, had some inkling that what they were doing was wrong. However, they proceeded, obeying authority or company rules, in a way reminiscent of the classic Milgram experiments.

The following articles, available in the library or the Internet, discuss the case:

"Arthur Andersen fires an executive for Enron orders," by Richard A. Oppel, Jr., The New York Times, January 16, 2002, pp. A1, C7., and "Andersen fires partner it says led shredding of Enron documents," by Ken Brown, Greg Hitt, Steve Liesman, and Jonathan Weil, The Wall Street Journal, January 16, 2002, pp. A1, A18.

How does the Andersen executive's behavior fit the mold of obedience to authority? How can we explain his actions, psychologically? How might the executive explain his actions? How can we encourage people tempted to commit crimes of obedience to listen to voices of conscience?

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